Methods developed in our laboratory have permitted the preparation of highly purified human pituitary FSH, LH, TSH, PRL and GH in sufficient quantities. From the purified FSH and LH each, we have isolated an alpha, the hormone non-specific and a Beta, the hormone specific subunit. These subunits have been combined to restore hormonal activities. We propose to study the primary amino acid and carbohydrate sequence of these fragments will be determined by conventional methods using paper chromatography amino acid sequenator and gas liquid chromatography. Mechanism of hormone action at the receptor site will be investigated by the administration of radio-isotopically labeled or unlabeled hormone into male and superovulated female rats. Distribution of the hormone in various sub-cellular fractions of the gonads will be studied. Identification, purification and characterization of the receptor protein will be performed by conventional methods used in protein chemistry. Antisera to FSH, LH and TSH and their subunits will be prepared in rabbits and guinea pigs. Hormone specific antibodies will be prepared by rivanol precipitations, immunoabsorption and immunochromatography on Sephadex. These antibodies will be used in the immunochemical characterization of hormones and their subunits, in the effect of hormone specific antibodies on the histology and steroidogenesis of the gonads will also be studied in experimental animals.